Device for distant control



April 1937- H. EBERHARD ET AL 2,077,314

DEVICE FOR DISTANT CONTROL Filed Dec. 23, 1932 Jm/e 0m: 1 my W Patented Apr. 13, 1937 FFICE r Heinrich Eberhard and Walther Gutzke, Berlin, Germany Application December 23, 1932, Serial No. 648,616 In Germany December 24, 1931 4 Claims.

The subject matter of the invention is a supervisory or checking device, which may be employed for distant control, for example, for wave control, especially'of radio transmitters the regu 5 lation of circumferential velocities, or also for all other purposes in which there is required the distant indication of desired values.

The device operates with the use of piezoelectrical frequency normals of the kind known per se. Arrangements of this kind are known in themselves. The subject matter of the application, however, differs fundamentally from these known arrangements by the fact that the piezoelectrical frequency standard is employed solely as relay, which serves the purpose of completing a stationary circuit, which in turn is capable of controlling an amplifying arrangement, in the anode circuit of which there is provided a desired indicating or control instrument.

By the combination of two frequency standards in the connection system according to the -invention it is furthermore possible to obtain extremely simple regulation or control of a desired machine-for example, of a radio transmitterwithin extremely narrow frequency limits, as the frequency standards employed permit of balancing up to within very few periods.

Two forms of embodiment of the arrangement according to the invention are illustrated by way of example in the drawing.

Fig. 1 shows an arrangement with merely one frequency standard, such as may be employed for desired checking purposes in connection with suitable arrangement for distant control. Fig.

2 illustrates an arrangement having two frequency standards to be employed for the same purposes. In this Fig. 1, l is the input circuit coil. A choke coil 4, the input coil l, a frequency standard 2, another choke coil 3 and a resistance 1 are connected in series in the order named across a D. C. source 6. A con-denser 5 is connected across the frequency standard 2 and the input coil l. The terminals 8 and 9, which may be the input terminals of an amplifying arrangement, are connected across the resistor I. Naturally, the signaling instrument may be connected in immediate fashion at 8 and 9 if desired. In the state of rest the battery circuit 6, 4, I, 2, 3, 8, 1, 9 is interrupted at 2. If, however, the frequency standard is excited by a frequency which is equal to its own frequency, there is formed in the oscillator valve 2 an ionized conductive path, by means of which the battery circuit is completed, so that the indicating instrument connected with the terminals 8 and 9 now indicates and the input coil the passage of current. Since the ionizationis directly proportional to the intensity of the high frequency received, the arrangement also permits of recording of the strength of the oncoming impulses. The arrangement is extremely sensi- 5 tive, as the actual control current is taken from the stationary battery, which may be such that even in the case of the least ionizationthat is to say, when the high frequency impulses received are merely very weak, an adequate con- 10 trol effect is attained.

In Fig. 2, a choke coil 3, a frequency standard 2, an input coil !,a choke coil 4 and a resistance 'l and condenser It in parallel are connected in series in the order named across a D. C. source 6, V 15 the positive terminal of said source being connectedto the-choke coil-3. A second D. C. source 6 is connected to have its positive terminal connected to the negative terminal of the s ume- 6' and its negative terminal connected through a choke coil 3' to one terminal of a second frequency standard 2. The other terminal of the frequency standard 2' is connected to the terminal of the frequency standard 2 which is directly connected to the input coil. A condenser 5 is connected across the frequency standard 2 An amplifying valve has its cathode and grid connected across the parallel combination of condenser I0 and resistance 1 in series with the conventional grid biasing battery 30 [2. The battery I3 is connected to heat the cathode of the valve. Connected between the anode and cathode of the valve is an indicating or control instrument H5 in series with a battery l8. Coupled to the input coil I is a transmitter having a capacity frequency control means and this transmitter may be controlled in frequency by the instrument iii in a well known manner. If now by reason of a high frequency impulse received at I one of the two oscillators 2 and 2 40 is excited so as to oscillate, the grid of the amplifying valve will be charged either positively or negatively, the feed current of the indicating instrument correspondingly amplified or weakened, and the instrument moved out of the position of 45 rest in the one or the other direction. If, for example, the frequency standard 2 is excited by oncoming high frequency oscillations of its own frequency, the circuit l, 2, 3, 6', I, 4 is completed at 2, the grid of the amplifying valve 50 charged positively, and the feed current of the indicating instrument amplified. If on the other hand the oscillator 2 is excited, the circuit I, 2', 3', 6, l, dis completed at 2, the grid of the amplifyingvalve charged negatively, and the feed 55 current of the weakened.

It will be readily apparent that in this manner a desired generator or any other corresponding arrangement may be maintained constant within two extremely narrow limits, which are determined by the difi'erence in frequency of the two frequency standards. It is possible, for example, in this manner to maintain constant a .high

instrument. correspondingly frequency transmitter, after the same-has beenonce regulated in accordance with the feed current position, within the narrowlimits determined by the difference between thetwo frequency standards, with the assistance of suitable regulating means, for example means which vary the capacity of the transmitting circuit. Conveniently the regulationofa. transmitter of this kind may be performed in the first-place manually with use of the optical effect (lighting) of the oscillators 2 and 2' as regulator, and after effected regulation a mechanical regulating meansconnected, ,which is'controlledby the arrangementaccordingto the invention and then maintainstheconstancy of the transmitter. The two condensers 5 .and. 5' are preferably each of 10,000

cm... and the condenser 10 is furnished with a size.-of.24 F and serves to prevent shortpendulumqmotionss The potential of the. batteries 6 and .6 requires to be such that it is not sufficientin. itself, to maintain theionization (1ighting) effect in the oscillator, so that passage of the.

the assistance of two :piezo-electrical oscillators.- 45 or-resonators, which-are suitablyconnected, in-

such: fashion that the same remains constant with-inthe-Jimitsadetermined by the difference in frequency .between. the piezo-electrical standards.

Weclaim:

50 1.1 In-a pieztweleetricv relaying devicefor dis: tant control by variations of the normal frequency of ,electrical oscillations,- two oscillatory circuits withg-atcommon einput coil, eachof said .circuits containing a piezo-electric resonator, a condenser and said common input coil in series, each of said piezo-electric resonators consisting of a piezoelectric crystal between two electrodes in a gasfilled tube, the one of said oscillatory circuits tuned to a frequency greater than said normal controlling frequency, and the other oscillatory circuit tuned'to a frequency smaller than said normal frequency, two sources of potential connected to-- gether in series and having two outside terminals, means for connecting one of said terminals between one of said crystals and its condensers, meansfor connecting the other of said terminals between said other crystal and said other condenser and 'relayingmeans connected between a point between said sources and a point between saidicommoninputcoil and said condensers.

2. Ina piezo-electric relaying device for distant control by variations of the normal frequency of electrical oscillations, two oscillatory circuits with a common-input coil, eachof said circuits containing a piezo-electric resonator, a condenser and said common input coil in series, each of said:

piezo-electric. resonatorsconsisting of a piezoelectric. crystal between two electrodes in a gas.-

filled tube, the one of said oscillatory circuitsv tuned to a frequency greater thanisaidnormal.

controlling frequency, andthe other oscillatory circuit tuned to a frequency smaller than said normal frequency, two sources of potential .6011";

nected together in series and having two-outside terminals, means for connectingone of said.ter'

minals betweenone of said crystals and its .con-. denser, means for connecting theother of said. terminals between said other. crystal and. said. other-condenser, an amplifying..tube having. an

anode, cathode .and grid, conductive means connected between .said cathode-and grid, a connec-:

tion between said .cathode and a point between said sources,--.a connection between saidgridtand a point between said condensersand said input.

coil through a choke coil and a relaying device connected between said anodeand said cathode.

3.. A device-according to claim 2, in which:said1 conductive means is a :gridleakresistance and in which a condenser is connected'thereacross.

4. A device accordingto. claim. 2, and additionally a frequency controllable transmitter whose output iscoupled to said input coil j and means whereby said relayingdevice controls the frequencyof said transmitter.

HEINRICH .EBERHARD. WALTHER GUTZKE. 

